Sound masking systems are widely used in offices and similar workplaces where an insufficient level of background sound results in diminished speech and conversational privacy. Such environments typically suffer from a high level of noise distractions, and lower comfort levels from an acoustic perspective. Sound masking systems operate on the principle of masking, which involves generating a background sound in a given area. The background sound has the effect of limiting the ability to hear two sounds of similar sound pressure level and frequency simultaneously. By generating and distributing the background noise in the given area, the sound masking system masks or covers the propagation of other sounds in the area and thereby increases speech privacy, reduces the intrusion of unwanted noise, and improves the general acoustic comfort level in the area or space.
Sound masking systems are of two main types: centrally deployed systems and independent self-contained systems. In a centrally deployed system, a central noise generating source supplies a series of loudspeakers installed throughout the physical area or space to be covered. The independent self-contained system comprises a number of individual self-contained sound masking units, which are installed in the physical space. The sound masking units operate independently of each other. More recently, sound masking technology has been applied to workstation environments. Such systems allow an occupant to control the sound masking in an individual workstation.
Such systems suffer a number of drawbacks. First, the individually controllable sound masking units by their very nature do not allow for consistent coverage of the masking sound through the entire space encompassing the workstations. This inconsistency in distribution of the masking sound results in variations in the sound masking level, which can irritate occupants. Second, the individual controllability of the sound masking units means that a workstation occupant wishing privacy has no control over the neighboring workstations and their respective sound masking levels. As a result, individually controllable sound masking units can, at most, reduce distractions, but they cannot ensure privacy because, for example, a workstation neighbor may have the sound masking turned off or set at a low level, which does not provide for sound privacy. Third, individually controllable sound masking units do not provide overall system or facility control. For example, it is not possible to provide timer functions and other centralized control functions.
Accordingly, there remains a need for improvements in the configuration and/or control of individual sound masking units.